Percolation of single-walled carbon nanotubes in ceramic matrix nanocomposites

• Published in: Acta materialia 2004-02, Vol.52 (4), p.1061-1067
• Main Authors: Rul, S., Lefèvre-schlick, F., Capria, E., Laurent, Ch, Peigney, A.
• Format: Article
• Language: English
• Subjects: Cermets, ceramic and refractory composites; Chemical Sciences; Cross-disciplinary physics: materials science; rheology; Electrical conductivity; Engineering Sciences; Exact sciences and technology; Hot-pressing; Material chemistry; Materials; Materials science; Nanocomposite; Nanoscale materials and structures: fabrication and characterization; Nanotubes; Other materials; Percolation; Physics; Scanning electron microscopy; Specific materials
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2003.10.038

The percolation of carbon nanotubes (CNT) in an electrical insulating ceramic is studied for the first time. The in situ synthesis of the CNT (0.2–25 vol%) by a CCVD route allows to achieve their homogeneous distribution in the spinel matrix. Up to 11 vol% CNT, the DC electrical conductivity ( σ) is well fitted by the scaling law of the percolation theory σ= k( p− p c) t with a low percolation threshold p c=0.64 vol%. At the threshold, σ jumps over seven order of magnitude (from 10 −10 to 0.0040 S cm −1) and then reaches a maximum at 8.5 S cm −1. The results are discussed in relation with the characteristics of the CNT, their damaging during the hot-pressing at 1300 °C and the microstructure of the composites. CNT-ceramic composites become attractive materials not only for their enhanced mechanical properties, but also for the possibility to tailor the electrical conductivity through the CNT content.